timing topping off at 14 at WOT.. ... help?

[Mitsumanny]

to the tuning gurus out there.. I've got a 2g w/ Evo 16g, front mount, denso 660's, walbro 190, dsmchips, afc, 2.5 exhaust, etc. Question is, i've been logging my runs on third gear and timing seems to clime nicely until 6K when it reaches 14 degrees and stays there. And this is w/o indication of knock per the knock gauge (dsmchips mod), and when i lean out it'll knock. I've richened it to +10% on 6K to get the same 14 degrees. I'm stumped right now, and it's so rich that i'm getting .98 O2's w/ little or no advance in timing from 6K on. Any advice is well appreciated.... help?....

 

[1fast97gsx]

.98 seems very rich

 

[Mitsumanny]

.98 certainly does. But that's the only way the car won't knock under 19 - 20 psi. I just ordered water injection and a wideband to see if i can tune this better.

 

[jérôme]

try retarding your base timing a little

 

[espinelli]

try retarding your base timing a little

don't you mean advancing base timing?

 

[kpt4321]

Something is wrong. If you're really getting 14 degrees of advance, then you have knock, or high coolant temps, or high intake temps, or something.

The least timing advance you will ever get from the timing map above 6000 rpm is like 16 degrees, and 15 degrees at 6000 rpm. As such, something else is pulling your timing down.

 

[Mitsumanny]

Thanks for the replies. I'm thinking perhaps my intercooler might be a little too small for the 19 - 20 psi i'm asking the turbo to boost. Sure it's a front mount, but it is the RRE one from a Griffin I/C. Hmmm. Looks like i've got more tuning to do. I just find it odd that the climb would be steady up until 6K where it's flat at 14. I richened it up and it was the same thing (w/ just one 15 reading between 6250 and 6500). thanks again for the reply. Hopefully i get this sorted out.

 

[kpt4321]

That intercooler should be fine.

What are your coolant and air temps when this is happening? That might be the issue.

 

[karbon]

Could be worse...I only get 11-12 degrees of timing at WOT. Have yet to get to the bottom of it.

 

[Violater101]

I believe the max timing the car will retard is 1 degree for intake temps above ~82 degrees and 2 degrees for coolant temps. I think its like 1 degree for anthing over 206 and then 2 degrees for anything over 216 (I can't remember the exact temps at which this occurs, but I am fairly confident its 2 degrees max). It is puzzling though that you are only seeing 14 degrees max with an AFC. I could understand that if you were using the DSMLink, but your not. You could be getting "Rich" knock as well. It's really hard to rely on 02's. My car likes to be around 10.9 to 11.0, otherwise it will knock.

 

[44pirate]

Turn the boost down to 15 and log a run. See if you get more timing. Like said above what is your coolant temp?

 

[Mitsumanny]

I didn't log coolant temp, but i do bet that it has alot to do with it. It's been hot here in southern cali and my car been heating up quite abit. For cooling tho i have a fluidyne, spal fan and a a/c fan wired to stay on. wondering now if it has to do w/ bad coolant (i used the one with dexcool by accident). i'm logging tonight so we'll see.

 

[espinelli]

Do you have a stock ECU? If so, then I believe 14* is about right. Also, you can't change the base timing on a 2G DSM unless you've done a 1G CAS converstion. Unless you have an earlier 2G model which came stock with a so called '1G CAS'

 

[myblack98gst]

if you have the dsmchips mod I am assuming you have a Eprom ECU in it.. try putting the stock ECU back in and see what your getting then...

I have a semi-similar setup but I am using:
big 16g Lots-0-porting, denso 720cc's, 3" turbo back, built 9.0:1 compressio0n 6 bolt..


I ran a log last night at 25 psi and I was still getting 20* of timing by 6k rpms
at 20 psi I got up to 26* timing at 7,500 rpms.

these were both with the o2 voltage at .90

 

[Mitsumanny]

thanks for the advice guys. I made this my perfect excuse for getting water injection to 'band aid' (cough) the situation. i'm gonna try to see how it reacts to the afc leaning things out a bit more up top but maintain intake temps by injection. we'll see tomorrow.

 

[espinelli]

thanks for the advice guys. I made this my perfect excuse for getting water injection to 'band aid' (cough) the situation. i'm gonna try to see how it reacts to the afc leaning things out a bit more up top but maintain intake temps by injection. we'll see tomorrow.

So are you running with a stock ECU?

 

[mad_trbo]

There is mention of a timing map and how above 6000 rpm the ecu won't pull timing more than 1 degree for 82 degree coolant temperature. Is there a table somewhere one could look at to see what timing should be certain RPM certain airflow, temperature etc....

How do people know that only 1 degree is going to be pulled. I think a table would be very helpful information, does one exist as public domain?

 

[espinelli]

There is mention of a timing map and how above 6000 rpm the ecu won't pull timing more than 1 degree for 82 degree coolant temperature. Is there a table somewhere one could look at to see what timing should be certain RPM certain airflow, temperature etc....

How do people know that only 1 degree is going to be pulled. I think a table would be very helpful information, does one exist as public domain?

84? You must mean intake temps not coolant temps. Coolant temps are much higher. At any rate, if coolant temps are below 206F you will get full timing. If they are above 206 and below 224F you lose one degree of timing. If they are above 224 you will lose 2 degrees of timing.

As for intake temps, anything above 84F or below 34F you will lose one degree of timing. A stock ECU you will not advance no more than 14-16 degrees of timing under WOT. Hope that helps.

 

[kpt4321]

if you have the dsmchips mod I am assuming you have a Eprom ECU in it.. try putting the stock ECU back in and see what your getting then...

I have a semi-similar setup but I am using:
big 16g Lots-0-porting, denso 720cc's, 3" turbo back, built 9.0:1 compressio0n 6 bolt..


I ran a log last night at 25 psi and I was still getting 20* of timing by 6k rpms
at 20 psi I got up to 26* timing at 7,500 rpms.

these were both with the o2 voltage at .90

You're probably tuning with something like a SAFC, right? Therefore, you are lying to the ECU about the total airflow.

His DSMChips.com chip may have full injector compensation, which makes the two situations totally different.

 

[kpt4321]

thanks for the advice guys. I made this my perfect excuse for getting water injection to 'band aid' (cough) the situation. i'm gonna try to see how it reacts to the afc leaning things out a bit more up top but maintain intake temps by injection. we'll see tomorrow.

Water injection isn't going to help much if you are not knocking...

 

[Mitsumanny]

thanks again guys, the ecu i'm using is a 95 eprom w/ dsmchips to compensate for injector and everything that comes w/ the stage 3 package. i just got back from work and about to do some tuning. to pinpoint the exact problem i'm gonna do things one at a time and log to see the results. starting with changing my coolant and adding some water wetter from redline and possibly some other additive to help cooling. we'll see. thanks again. i am finding more and more excuses to go for the dsmlink... I think this weeks paycheck maybe headed in that direction...

 

[espinelli]

good luck. i recently installed dsmlink and i think its great.

 

[Violater101]

I know I've seem this somewhere, but I can't find out where. With a bigger sized turbo with a stock ecu, the most timing the car will get is 16 degrees from 6500 up correct? If its a smaller sized turbo, then the car may get more than 16 degrees because of the amount of air its flowing?

 

[ahains]

I know I've seem this somewhere, but I can't find out where. With a bigger sized turbo with a stock ecu, the most timing the car will get is 16 degrees from 6500 up correct? If its a smaller sized turbo, then the car may get more than 16 degrees because of the amount of air its flowing?

Disregarding valve overlap in conjunction with reduced turbine backpressure (secondary effects only), any two turbo will flow essentially the same *volume* of air at a given PSI.

It is true that a larger compressor can flow more air *total*, but this is because it can do so at a higher PSI. For instance, you stock turbo may not be able to generate greater than 25psi with the wastegate line disconnected, yet a bigger compressor can do 30psi and at a much lower shaft speed and also significantly lower temperature.

Perhaps you are thinking of running larger injectors and leaning fuel by modifying the air flow signal?

HTH,
Adrian